Elisa Lam of Vancouver, British Columbia, is seen in this undated handout photo provided by the Los Angeles Police Department. A body was found in a large water tank on top of a downtown Los Angeles hotel on February 19

Sources within local law enforcement agencies say they are still unsure over events leading to the death of Canadian tourist Elisa Lam. Sources indicate it is still too early to consider the case a homicide.

Elisa Lam, 21, was last seen in the 600-room Cecil Hotel in Los Angeles on 31 January. She was then found, dead, in a water tank in the same hotel.

The body was found by a maintenance worker investigating the cause of low water pressure. Authorities believe Lam travelled to California from Vancouver on 26 January.

An autopsy on Lam's body has been scheduled for Thursday and it remains possible the young woman died of accidental causes. Investigators hope any evidence of trauma will be documented in the post-morterm report.

A Los Angeles Times report adds police are also investigating Lam's hotel room.

Meanwhile video footage released by police last week after Lam went missing raises more questions than answers.

The video, from a CCTV camera in a hotel elevator, shows Lam behaving strangely; she enters the elevator, pushes multiple buttons and then peeps out of the elevator, as if looking for an attacker. She then proceeds to step in and out of the elevator a few times.

Mid-way through the video, Lam is seen standing outside and appears to be talking to herself, while making rather elaborate hand gestures. Nobody else is seen in the video with her. She then exits the elevator and disappears from the camera's view.

The video, available on YouTube, has been extensively commented on, with some believing Lam seems drugged while others say an unidentified hand can been seen, towards the end of the clip, preventing the elevator door from closing.

One user wrote a rather extensive comment: "1:08-1:48 The stalker orders her to hold up her hands, instructs her to repeat pressing the floors in the elevator (in order to act normal). [Between] 1:46 [and] 1:51 she is threatened to step back outside the elevator.

"[Between] 1:51 [and] 2:27 She is ordered to look at the surveillance camera (1:54) and then act like she's stupid/drunk/drugged/crazy (at 2:22 you can see stalker's hand keeping the doors from closing, clearly he wants you to *think* she's crazy) 2:27 and beyond: A tragedy."

Another wrote: "Please don't believe the HAND THEORY at 2.22 it's not a hand it's the angle of her foot turning around...her slipper...look again."